Speed Velocity and Distance Time Graph II

What is speed defined as?

• The distance traveled by an object in a unit of time

• The total distance covered in a journey

• The rate of change of position

• The rate at which an object changes direction

Answer explanation

Speed is defined as the distance traveled by an object in a unit of time. This means it quantifies how fast an object moves, making the first choice the correct answer.

Which of the following is a vector quantity?

• Velocity

• Distance

• Time

• Speed

Answer explanation

Velocity is a vector quantity because it has both magnitude and direction. In contrast, distance and speed are scalar quantities, which only have magnitude, and time is a measure of duration without direction.

What is the SI unit of speed?

• Centimeters per second (cm/s)

• Miles per hour (mph)

• Meters per second (m/s)

• Kilometers per hour (km/h)

Answer explanation

The SI unit of speed is meters per second (m/s). It is the standard unit used in scientific contexts, making it the correct choice among the options provided.

What does average speed measure?

• Total displacement over total time

• Total distance over total time

• Speed at a specific moment

• Distance in a specific direction

Answer explanation

Average speed measures the total distance traveled divided by the total time taken. It does not consider direction or specific moments, making 'Total distance over total time' the correct choice.

What is the formula for average velocity?

• v = d/t

• v = Δd/Δt

• v = s/t

• v = d/s

Answer explanation

The formula for average velocity is v = Δd/Δt, where Δd is the change in distance and Δt is the change in time. This choice correctly represents average velocity as it accounts for the total distance traveled over the total time.

What does a horizontal line on a distance-time graph indicate?

• The object is moving back to the starting point

• The object is accelerating

• The object is stationary

• The object is moving at a constant speed

Answer explanation

A horizontal line on a distance-time graph indicates that the distance remains constant over time, meaning the object is not moving. Therefore, the correct choice is that the object is stationary.

If an object moves in a straight line without changing direction, what can be said about its average speed and average velocity?

• Average velocity is greater than average speed

• They are equal

• They are always different

• Average speed is greater than average velocity

Answer explanation

When an object moves in a straight line without changing direction, its average speed (total distance/time) and average velocity (displacement/time) are equal, as displacement equals distance in this case.

What is the average speed of a rabbit that hops 6 meters in 11 seconds?

• 0.57 m/s

• 0.56 m/s

• 0.55 m/s

• 0.54 m/s

Answer explanation

To find the average speed, divide the distance by time: 6 meters / 11 seconds = 0.545 m/s. Rounding to two decimal places gives 0.54 m/s, which is the correct answer.

What does a steeper slope on a distance-time graph indicate?

• The object is moving back to the start

• The object is moving slowly

• The object is stationary

• The object is moving quickly

Answer explanation

A steeper slope on a distance-time graph indicates that the distance is changing rapidly over time, meaning the object is moving quickly. Therefore, the correct choice is that the object is moving quickly.

What is the average speed of a car that travels 70 km in 2 hours?

• 35 km/h

• 40 km/h

• 45 km/h

• 30 km/h

Answer explanation

To find the average speed, divide the distance by the time. Here, 70 km ÷ 2 hours = 35 km/h. Therefore, the average speed of the car is 35 km/h.